Hitachi, Ltd.

Hitachi Communication Technologies, Ltd.

Other

Mitsubishi Electric Corporation

Jeol Ltd.

Alaxala Networks Corporation

Hitachi Information Technology Co., Ltd.

Kenichi Sakamoto

Koji Wakayama

Tohru Kazawa

Noboru Endo

Masahiko Mizutani

Masaru Murakami

Tsutomu Kusaki

Yoshihiro Ashi

Takashi Yokoyama

Masayuki Takase

Kazuyoshi Hoshino

Ryosuke Nishino

Toshiki Sugawara

Norihiko Moriwaki

Shiro Tanabe

Hideki Endo

Takeshi Aimoto

Hiroki Ikeda

Kazuho Miki

Nobuyuki Yamamoto

Akihiko Takase

Takayuki Kanno

Akio Makimoto

Kazumasa Yanagisawa

Shinichi Akahane

Kazuma Yumoto

Takahisa Miyamoto

Nobuhito Matsuyama

Michitaka Okuno

Atsushi Iwamura

Taishi Shinagawa

Takeshi Shibata

Hiroaki Miyata

Kazuo Sugai

Atsushi Kiuchi

Tetsuhiko Hirata

Koji Fukuda

Tatsuhiko Miyata

Norihiro Sakamoto

Hiroki Yano

Minoru Hidaka

Takayuki Yamaoka

Hidehiro Fukushima

Masato Terada

Satoshi Kiyoto

Tomohiro Baba

Satoshi Kiyotou

Nobuo Ogasawara

Hirofumi Nakakoji

Takashi Zokoyama

Kojii Wakayama

This sample rack conveying apparatus is provided with a pusher unit, a linear motion guide, and a conveyance drive mechanism. The pusher unit has a base portion, a moving member, and a base-side guide. The base portion is supported by the linear motion guide so as to be movable in a first guide direction. The moving member is provided with a pusher that pushes a sample rack. The base-side guide supports the moving member such that the moving member is movable in a second guide direction that crosses the first guide direction.

Sample rack conveying apparatus and automated analysis system

To provide a sequence-program-component creation program that causes a computer to perform a searching step of searching an overall circuit of a sequence program for a common logic part and extracting a logic pattern that appears in common in a circuit pattern arranged in the common logic part as a common circuit pattern, a component-candidate displaying step of displaying an extracted common circuit pattern as a candidate for a program component, a component registration setting step of registering a common circuit pattern selected by a user from candidates for the program component, and a replacing step of replacing the common logic part of the sequence program with the program component.

Sequence-program-component creation program and sequence-program-component creation device

A data communication apparatus to be coupled to a first network and a Multiprotocol Label Switching (MPLS) network, includes a receiving unit which receives a data including header information indicating a destination and first header information used to identify a first Virtual Private Network (VPN) in the first network. The apparatus also includes a transmitter which transmits data having added thereto a MPLS header information used to identify one of the plurality of second VPNs in the MPLS network, the MPLS header information corresponding to both the header information indicating the destination and the first header information used to identify the first VPN in the first network included in the received data.

VPN composing method, interwork router, packet communication method, data communication apparatus, and packet relaying apparatus

The present invention provides an IP broadcasting system that can receive IP broadcasting videos over an IP multicast network. In the IP broadcasting system, a multicast group management apparatus for IP broadcasting that holds multicast group identifiers is connected via an IP multicast network over which IP broadcasting services are provided. When a user issues a request to switch an IP broadcasting channel from an IP broadcasting terminal, a query message including the requested IP broadcasting channel identifier is transmitted to a management apparatus. The IP broadcasting terminal receives a response message indicating the correspondence between the IP broadcasting channel identifier and a multicast group identifier, and transmits a video reception request message to a multicast group by using the received multicast group identifier.

IP broadcasting system and a multicast group management apparatus for the same

Provided is an optical access system, including: an optical line terminal, a plurality of optical network units and an optical switching unit. The optical line terminal sends to the optical switching unit a control frame including a switching time when the optical switching unit is to make a switch from one of the optical communication paths between the optical line terminal and the plurality of optical network units to another, and an identifier of an optical communication path to which the switch is made in order to switch the optical communication paths between the optical line terminal and the plurality of optical network units. The optical switching unit switches the optical communication paths between the optical line terminal and the plurality of optical network units based on the switching time and the identifier of the optical communication path after switching which are included in the control frame.

Optical access system, optical switching unit and optical line terminal

Provided is an optical access system comprising: an optical line terminal connected to another network; a plurality of optical network units, each connected to a user terminal; and at least one of an optical switching unit and an optical splitter, which is installed between the optical line terminal and the plurality of optical network units. The optical line terminal allocates a length of time to a discovery phase for detecting the plurality of optical network units, and a length of time to data transmission phases for transferring data from the plurality of optical network units; and changes a ratio of the length of time of the discovery phase to the length of time of the data transmission phases so that the length of time of the discovery phase is shortened in the case where a number of the optical network units that are registered in the optical line terminal increase.

Optical access system and optical line terminal

To prevent, in using a multicast DA in an OAM frame, an increase in the network bandwidth usage and in the load of node processing and a degradation of the network reliability caused by a frame being transmitted to all routes in a broadcast domain. A MAC address and other basic frame information and the MEGID are associated with each other, and the MEGID information is added to the OAM frame, and these information are transmitted from an edge node serving as an end point of an ME. In a relay node of the ME, a route control table used for OAM frame control is provided, and a filter is generated by snooping of the OAM frame. Furthermore, when the relay node does not support the OAM function, the MEGID is denoted by a VLAN tag and the route control is made using the snooping function of each VLAN tag.

Network system and data transfer device

A clock data recovery circuit that supplies stable reference clocks to the object respectively by shortening the time of bit synchronization with each received burst data signal regardless of jittering components included in the received burst data signal, includes an interpolator that generates a reference clock having the same frequency as that of a received burst data signal and two types of determination clocks having a phase that is different from that of the reference clock respectively; and a phase adjustment control circuit that can change the phase of the reference clock in units of M/2&#x3c0;. After beginning receiving of a burst data signal, the clock data recovery circuit sets a large phase change value at the first phase adjustment timing and reduces the change value in the second and subsequent phase adjustment timings, thereby realizing quick bit synchronization with the received burst data signal to generate a reference clock.

Clock data recovery circuit

An optical access system capable of avoiding cutoffs or interruption in the periodically transmitted signals that occur during the ranging time is provided. A first method to avoid signal cutoffs is to stop periodic transmit signals at the transmitter during the ranging period, and transmit all the periodic transmit signals together when the ranging ends, and buffer the signals at the receiver to prepare for ranging. A second method is to fix definite periods ahead of time for performing ranging, then cluster the multiple periodic transmit signals together in sets at the transmitter and send them, and then disassemble those sets back into signals at the receiver. The transmitting and receiving is then controlled so that the transmit periods do not overlap with the ranging periods. In this way an optical access system is provided that can send and receive signals requiring periodic transmissions without interruption even during ranging operation.

Optical access system

In a PON system with WDM, at the time of initial setting, each ONU negotiates with an OLT, and automatically acquires a wavelength which can be used by the ONU. One wavelength for negotiation of assigned wavelength is fixed as a default, and a newly connected ONU first uses the wavelength. The OLTincludes a plurality of light sources for downstream communication. The ONUincludes a wavelength variable filter selectively receiving one of wavelengths of downstream communication, and a wavelength variable light source selectively emitting light of one of plural wavelengths for upstream communication. The ONUuses a transmission wavelength (for example, &#x3bb;u) for negotiation and transmits a wavelength assignment requestto the OLT. The OLTselects a wavelength &#x3bb;uto be assigned from unused wavelengths, and transmits wavelength information to the ONU. The OLTand the ONUcommunicates using the notified wavelengths.

Passive optical network system and wavelength assignment method

In a GPON system conforming to ITU-T Recommendations G.984.3, an optical line terminal is provided which has an active bandwidth allocation function that preferentially puts small bandwidth signals in a particular segment of a frame, e.g., at a head of the frame, to prevent fragmentations that may occur particularly when allocating small bandwidths of about 100 kbits/s.

Optical line terminal capable of active bandwidth allocation for passive optical network system

The invention realizes defect indication on a multipoint logical path and switching of the logical path using a transfer protocol of configuring a logical path in a ring network. A working path and a backup path are set up where each transmits a frame from a transmitting end node to multicast receiving end nodes, forwards the frame to the transmitting end node and terminates it at the transmitting end node after going around the ring. Any node detecting a defect transmits a forward defect indication frame to a multipoint logical path in which the defect occurs. The transmitting end node receiving the forward defect indication frame halts the use of the notified multipoint logical path, and transmits a frame in another path where the forward defect indication frame is not received. When received from both multipoint logical paths, the transmitting end node copies the frame and forwards them to both paths.

Network system and node

Disclosed herewith is a PON system and a bandwidth controlling method capable of controlling congestion with use of an upstream bandwidth in a PON section efficiently when congestion occurs in a gateway (GW) connected to an OLT. An OLT connected to a plurality of ONUs through a passive optical network (PON) and to a gateway (GW) through a communication line, when receiving a congestion occurrence notice indicating a congestion occurred output number from a GW, identifies the identifier of the ONU that is using a GW output line having the congestion output port number and shifts the bandwidth controlling of the PON section in a normal mode for allocating a bandwidth to each ONU normally to that in a bandwidth suppression mode for allocating a congestion time allowable bandwidth that is less than the current bandwidth to the ONU having the identified ONU identifier and a bandwidth to each of other ONUs according to its transmission queue length.

PON system

In a PON system by WDM, IP broadcast can be received without oppressing a band used by a user for Internet communication. An OLT provides a first wavelength received in common by respective ONUs and plural second wavelengths by which the OLT and the respective ONUs perform communication individually. With respect to signals in the downstream direction, each of the OLTs includes a transmitter to transmit the first wavelength and plural transmitters to transmit the second wavelengths used for the individual communication with the respective ONUs. Each of the ONUs includes a receiver to receive the first wavelength and a receiver to receive the second wavelength used in the ONU itself. The OLT transmits data of the IP broadcast by the first wavelength and transmits individual data of each of the ONUs by the second wavelength corresponding to the ONU.

Passive optical network system, optical line terminal, and optical network unit

Growing community of inventors

Kokubunji, Japan

Kenichi Sakamoto